Normally a wiper system includes a support frame onto which an electric motor is fixed and which, furthermore, carries three bearing bushes for a wiper shaft, each bearing bush being driven by the motor via appropriate gearing elements, namely cranks and push rods. Usually these parts are pre-assembled as a unit by the manufacturer of the wiper system, and the unit is then delivered to the manufacturer of motor vehicles.
A wiper system also includes the wiper arm-and-blade assemblies which can be fastened to the wiper shafts. These wiper arm-and-blade assemblies have a wiper arm and a wiper blade mounted thereto. Each of these parts is also separately delivered to the manufacturer of motor vehicles by the manufacturer of wiper systems and, there, they are mounted onto the car body of the motor vehicle after the assembly of the support frame.
Such assembly of a wiper system to a motor vehicle is awkward. Moreover, there is a danger of assembling it wrongly, if one does not take care--by making increased logistic efforts--to put the parts, which belong together, but have been delivered separately, together again on the assembly line of the motor vehicle. Since in some motor vehicles the left wiper arm-and-blade assembly differs from the right one, for instance the wiper blade on the driver's side often has a spoiler for increasing the pressure, even when making increased logistic efforts mistakes regarding the assembly cannot totally be excluded.